High blood count in children refers to the elevation of white blood cells in the blood, which is mostly caused by physiological factors, infectious diseases and so on. 1. Physiological factors: the baby’s lymphocytes are high in childhood, if the blood test is high, only slightly elevated, not accompanied by other symptoms, it is recommended to closely observe, and consider that it is related to the physiological elevation of white blood cells. As the baby grows up, the proportion of lymphocytes may gradually decrease. 2. Infectious diseases: high white blood cells can also be considered related to infectious diseases, such as bacterial infections caused by pneumonia, suppurative tonsillitis, may lead to elevated white blood cells, neutrophils. Viral infections such as measles, in addition to elevated blood counts, lymphocytes may also be significantly elevated. Children with high blood count, if it is caused by physiological factors, usually do not need special treatment. If it is suspected to be caused by certain diseases, it is recommended to go to the pediatrics department of the hospital in time to understand the cause and get timely treatment.